THE SIFAKAS. 97 
The characters which distinguish this genus from Avahis and 
/ndris are the following : The fur with which they are covered 
is more silky than woolly, and‘in general appearance is white, 
more or less washed with yellow, varying to red or black. 
The head is very slightly longer than it is broad, with a 
black and almost naked muzzle; the ears, half buried in the 
fur, are flatter and wider than in /zdris, the inner surface 
being naked and black, and the outer haired. The nostrils 
are large and semilunar in shape. The tail is long. The 
index-finger is not united by a membrane to the others ; their 
hands and feet are in a much less degree organs of prehension 
than in most of the other Lemurs. 
The skull in proportionate length is intermediate between 
that of Avahis and /ndris. Compared with Avahis it is less 
vaulted, its muzzle is longer, and the orbits are smaller. The 
space between the eyes is high, and not depressed, on account 
_ ofthe presence of a large air-cavity in the underlying bone. 
Their nasal bones do not reach as far forward in front as the 
level of the incisor teeth. In the dentition of the upper jaw, 
the incisors protrude somewhat in front, and are dilated 
laterally in a regular series—thus distinguishing the genus 
Propithecus from Lemur,-—the inner incisors being larger than 
the outer ones, with their tips approximating. Between the 
canine and the anterior pre-molar there is a short gap. 
The anterior and median molars have the cusps of the crown 
alternate; the posterior has them opposite. In the lower 
jaw the incisors are shorter and stronger than in Avahis, and 
the molars are four cusped. 
The genus Pvofithecus contains three species; (1) The 
Diademed Sifaka (P. diadema), (2) Verreaux’s Sifaka (P. 
3—V. I H 
